Interprofessional collaboration is central to quality patient care; however, little is known about developing interprofessional care plans, particularly in oncology. This article describes the development of an interprofessional care plan for an older adult woman with breast cancer. Two collaborative expert workshops were used; 15 clinical experts reviewed an online patient case and were asked to prepare a uniprofessional care plan. In workshop 1, participants worked from a draft interprofessional care plan, synthesized from the uniprofessional care plans by research associates, to arrive at consensus on an ideal interprofessional care plan. Using qualitative inductive content analysis of workshop transcripts, specific changes and overall key principles were identified and used to revise the draft plan. Based on these findings, a generalized interprofessional care plan/oncology model was developed. Revisions and proposed model were validated through consensus by participants during workshop 2. Participants highlighted the iterative, cyclical, and multilayered nature of patient care experiences; the importance of central patient profiles, which are contributed to and validated by all healthcare professionals; and the importance of assessing patient understanding. Participation of a patient representative provided an invaluable contribution. The process and model provide a unique framework for interprofessional care plan development in other settings and patient populations.